Regarding the diesel particulate filter (hereafter, DPF) which traps particulate matter contained in the exhaust gas of a vehicle diesel engine, JP2002-155726A published by the Japan Patent Office in 2002 discloses a regeneration method which eliminates the particulate matter which has built up on the DPF by combustion control of the air-fuel mixture supplied to the engine.
Specifically, when the engine is required to produce an acceleration, the air-fuel ratio of the air-fuel mixture supplied to the engine is enriched by throttling the intake throttle, and the temperature of the DPF is increased to burn the particulate matter deposited on the DPF by increasing the combustion temperature of the air-fuel mixture.